20241118 finished.

src/problem/mod.rs

@@ -322,3 +322,5 @@ mod p3239_minimum_number_of_flips_to_make_binary_grid_palindromic_i;
 mod p3240_minimum_number_of_flips_to_make_binary_grid_palindromic_ii;
 
 mod p825_friends_of_appropriate_ages;
+
+mod p661_image_smoother;

src/problem/p661_image_smoother.rs

@@ -0,0 +1,69 @@
+/**
+ * [661] Image Smoother
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn image_smoother(img: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
+        let (m, n) = (img.len(), img[0].len());
+        let mut result = vec![vec![0; n]; m];
+
+        let add = |x: usize, y: usize| {
+            img[x][y]
+                + if x + 1 < m { img[x + 1][y] } else { 0 }
+                + if x > 0 { img[x - 1][y] } else { 0 }
+        };
+
+        let grid =
+            |x: usize, y: usize| 1 + if x + 1 < m { 1 } else { 0 } + if x > 0 { 1 } else { 0 };
+
+        for x in 0..m {
+            let mut sum = add(x, 0);
+            let mut g = grid(x, 0);
+
+            for y in 0..n {
+                if y + 1 < n {
+                    sum += add(x, y + 1);
+                    g += grid(x, y + 1);
+                }
+                if y > 1 {
+                    sum -= add(x, y - 2);
+                    g -= grid(x, y - 2);
+                }
+
+                result[x][y] = sum / g;
+            }
+        }
+
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_661() {
+        assert_eq!(
+            vec![vec![0, 0, 0], vec![0, 0, 0], vec![0, 0, 0]],
+            Solution::image_smoother(vec![vec![1, 1, 1], vec![1, 0, 1], vec![1, 1, 1]])
+        );
+        assert_eq!(
+            vec![
+                vec![137, 141, 137],
+                vec![141, 138, 141],
+                vec![137, 141, 137]
+            ],
+            Solution::image_smoother(vec![
+                vec![100, 200, 100],
+                vec![200, 50, 200],
+                vec![100, 200, 100]
+            ])
+        );
+    }
+}